Panel

ABSTRACT

A floor, wall or ceiling panel comprises a core and a decorative top layer provided on the core. The core comprises a magnesium oxide-based board material, and wherein the aforementioned panel, on at least two opposite edges, is provided with coupling means allowing that two of such panels can be interlocked at the respective edges.

CROSS REFERENCE

This application is a continuation of U.S. application Ser. No.18/050,148, filed Oct. 27, 2022, which is a continuation of U.S.application Ser. No. 16/651,419, filed Mar. 27, 2020, now U.S. Pat. No.11,525,268, which is a nationalization of PCT Application No.PCT/IB2018/057059, filed Sep. 14, 2018, which claims the benefit under35 U.S.C. 119(e) to the U.S. provisional application 62/564,499 filed onSep. 28, 2017.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to panels, more particularly to floor, wall andceiling panels.

2. Related Art

More particularly, the invention relates to floor panels with asubstrate and a provided thereon decorative top layer. Such floor panelsare widely known as such, for example, from WO 97/47834. The floorpanels disclosed there relate to, amongst others, floor panels with acore which substantially consists of a HDF board with a laminate layerdirectly pressed thereon, said laminate layer comprising one or morepaper sheets impregnated in melamine resin, amongst which preferablyalso a paper sheet with a print in, for example, a wood or stone motif,namely a so-called decor paper.

It is known that the HDF substrate or the HDF core of such laminatepanel is sensitive to moisture influences. An exposure to excessivemoisture, for example, when wet-cleaning such floor, may result inexcessive swelling of the substrate and warping of the decorative toplayer, i.e., laminate layer. This then in its turn leads to acceleratedwear of the surface. A change in relative air humidity in the room leadsto expansion or shrinkage of the length and/or width of the panels,which makes it necessary to provide expansion joints at the edges of thefloor and in the surface of large floor surfaces. From the state of theart, a plurality of solutions for one or more of these problems areknown. From EP 2 248 665, a thermoplastic laminate plank is known whichcomprises a PVC substrate and a laminate layer provided thereon. From EP1 938 963, a floor panel is known with a core of soft PVC, wherein thedecorative top layer also is composed of PVC. Floor panels on the basisof thermoplastic materials are not or hardly influenced by moisture, butshow the disadvantage that they expand and shrink under the influence oftemperature changes. From WO 2016/156,506 a floor panel is known with acore of a fiber cement board. Such substrate shows an excellentdimensional stability under the influence of moisture and temperature.The weight of these boards leads to problems with packaging, ergonomicsand the safety of marketing, and with installation. In particular withpanels which are provided with mechanical coupling parts, such as in EP1 875 011, damage may occur during installation. The panels are so heavythat when connecting the coupling parts, for example, when turning thecoupling means into each other, undesired splitting forces may occurwhich can damage the coupling means and/or the substrate irreparably.

US 2017/268,118 discloses glass fiber-reinforced magnesium oxide boardmaterials for the use in building applications.

SUMMARY OF THE DISCLOSURE

The present invention primarily aims at providing an alternative panel,more particularly floor, wall or ceiling panel, wherein a solution isoffered for one or more of the problems with the panels of the state ofthe art.

To this aim, the invention, according to its first independent aspect,relates to a panel, more particularly a floor, wall or ceiling panel,wherein this panel comprises a core and a provided thereon decorativetop layer, with the characteristic that the aforementioned corecomprises a magnesium oxide (MgO and/or MgO₂) based board material andwherein the aforementioned panel, on at least two opposite edges, isprovided with mechanical coupling means allowing that two of such panelscan be interlocked at the respective edges. Magnesium oxide-based boardmaterials are dimensionally stable under the influence of moisture andtemperature, but can be made more light-weight than fiber cement boardson the basis of Portland cement. By making use of such core orsubstrate, panels can be obtained with a more limited risk of damageduring coupling of the mechanical coupling means. Such panels can bepacked better and can be more ergonomic and safer in use.

It is clear that with the magnesium oxide-based board materialpreferably a board material is concerned which substantially is obtainedfrom a watery slurry of magnesium oxide, wherein hardening takes placeby means of a chemical reaction comparable to the hardening reaction of,for example, cement.

The magnesium oxide board material preferably forms at least half of thethickness of the panel and/or forms at least half of the weight of thepanel. Preferably, the magnesium oxide board material forms the layerwith the highest density in the panel.

Preferably, the magnesium oxide-based board material comprises fillers.As fillers, wood particles, cork particles, bamboo particles, hempparticles, flax shives or other vegetable particles can be applied.According to another example, lime, talc of other stone-like powder orflour can be applied as a filler. Of course, also a mixture of bothtypes of fillers can be used.

Further, the magnesium oxide-based board material can also comprisereinforcement fibers, such as glass fibers, PVA fibers (polyvinylalcohol) or cellulose fibers, which, preferably more or less uniformly,can be distributed in the board material. By this measure, thebrittleness of such board material can be reduced.

Preferably, the magnesium oxide-based board material comprises at leasta reinforcement layer, preferably a glass fiber layer of the woven orunwoven type. The presence of a glass fiber layer offers variousadvantages. By means of a glass fiber layer, an increased coherence ofthe magnesium oxide-based board material can be obtained. A glass fiberlayer also allows to increase the impact resistance of the panel andincrease the dimensional stability still more. It is clear that one ormore of such reinforcement layers possibly can be embedded in themagnesium oxide board material together with separate reinforcementfibers. Preferably, the reinforcement layer relates to a glass fiber netwith openings, such that the actual board material is continuous throughthese openings.

Preferably, the aforementioned reinforcement layer is situated offcenter from the thickness of the magnesium oxide-based board material.In this manner, an increased bending stiffness of the board material,and the panel, is obtained. Preferably, said reinforcement layer, on theside thereof directed away from the aforementioned center, is flanked bya layer of magnesium oxide-based material, or, in other words, therespective reinforcement layer is entirely embedded in the magnesiumoxide board material. Preferably, said layer of magnesium oxide-basedmaterial, which is situated on the side of the reinforcement layer whichis directed away from the center, is free from fillers or comprises lessfillers than a central portion of said magnesium oxide-based boardmaterial, and/or comprises fillers with an average particle size whichis smaller than the fillers in a central portion of said magnesium-oxideboard material. By means of such embodiment, a better surface of theboard material is obtained, such that the risk of unevennesses showingin the decorative top layer or in/on the underside of the panels will berestricted.

According to a particular embodiment, the panel comprises at least twoof such reinforcement layers, which then preferably are situated onopposite sides of the center of said magnesium oxide-based boardmaterial, preferably with each time a layer of magnesium oxide-basedmaterial which is situated on that side of the respective reinforcementlayer which is directed away from the center.

Preferably, the aforementioned mechanical coupling means are realized atleast partially, and preferably entirely, in one piece with theaforementioned magnesium oxide-based board material.

The mechanical coupling means preferably are realized substantially as atongue and groove connection, wherein the groove is bordered by an upperlip and a lower lip.

Preferably, the mechanical coupling means show one or a combination oftwo of more of the following characteristics, which each separately orin any combination offer interesting advantages:

-   -   the characteristic that the coupling means offer a locking in        horizontal direction H1 as well as in vertical direction V1;    -   the characteristic that at least one pair of horizontally active        locking surfaces of the coupling means is realized in the        magnesium oxide-based board material;    -   the characteristic that at least one pair of horizontally active        locking surfaces of the coupling means is realized at least        partially and preferably entirely in the magnesium oxide-based        board material;    -   the characteristic that one or more pairs of the vertically        active locking surfaces are formed at least partially and        preferably entirely from the magnesium oxide-based board        material; the characteristic that the mechanical coupling means        consist of milled profiles which, for at least 70 percent of        their circumference, are provided in the magnesium oxide-based        board material of the invention;    -   the characteristic that the panels are rectangular and that a        first pair of opposite edges as well as a second pair of        opposite edges is provided with coupling means;    -   the characteristic that the mechanical coupling means allow a        coupling by means of a turning movement W along the respective        edges and/or a horizontal shifting movement S of the edges        towards each other and/or a downward-directed movement of a male        coupling part, for example, having a tongue, into a female        coupling part, for example, having a groove;    -   the characteristic that the lower lip extends in horizontal        direction to beyond the upper lip; the characteristic that in a        coupled condition of two of such floor panels a tension force is        obtained between the respective floor panels; herein the lower        lip of the groove preferably is in a bent condition;    -   the characteristic that the lower lip of the groove in a coupled        condition is bent; the characteristic that the coupling means,        on at least one pair of opposite edges, for example, on the long        edges in the case of a rectangular and oblong panel,        substantially are realized as a tongue and a groove, bordered by        a lower lip and an upper lip, wherein the lower lip shows a        standing portion which can cooperate with a locking groove        realized on the lower side of the tongue.

In the case that one or more reinforcement layers are applied in themagnesium oxide-based board material, the panel preferably shows one ora combination of two or more of the following characteristics:

-   -   the characteristic that the aforementioned reinforcement layer        extends uninterruptedly in the lower lip; this embodiment is        particularly interesting when a certain bendability of the lower        lip is required during coupling and/or thereafter;    -   the characteristic that the aforementioned reinforcement layer        extends uninterruptedly in the tongue; this embodiment is        particularly interesting with floor panels which have to be        coupled by means of a turning movement, as the weight of the        panels, amongst others, has an effect on the tongue; the glass        fiber layer restricts the risk of damage at the tongue;    -   the characteristic that the aforementioned reinforcement layer        extends uninterruptedly in the upper lip; such embodiment is        particularly interesting with coupling means which have to be        coupled by means of a turning movement, as the weight of the        panels, amongst others, has an effect on the upper lip; the        glass fiber layer restricts the risk of splitting off or        permanent deformation of the upper lip.

Preferably, said decorative top layer comprises at least a, preferablyprinted, decor. Such top layer can be obtained in various concrete ways,of which herein below some possibilities will be listed, as exampleswithout any limitative character.

According to a first possibility, said decorative top layer comprises acarrier sheet printed with a decor. Herein, this may relate to a papersheet or a plastic foil, such as a polyvinyl chloride (PVC) foil, apolyethylene terephthalate (PET) foil, a polypropylene (PP) foil, apolyurethane (PU) foil and the like. When this relates to a paper sheet,this preferably relates to a paper sheet which as such is provided, forexample, is impregnated, with a synthetic material, such as withmelamine resin, acrylate-based or acrylate-containing resin, PVC or PU.Such printed carrier sheet can either be bonded directly on themagnesium-based board material, or via one or more intermediate layers.The connection of the decorative top layer as a whole with the magnesiumoxide-based board material preferably is obtained via a glue layer.

According to a second possibility, the aforementioned decorative toplayer comprises a decor formed, more particularly printed, directly onthe panel. Herein, this may relate to a print by means of an inkjetprinter directly on the respective panel surface. Herein, the panelsurface can consist of the, whether or not pre-treated, surface of themagnesium oxide-based board material. Such pre-treatment can comprise agrinding treatment and/or a treatment with a filler, such that possiblepores in the surface are filled, and/or a treatment with an adherenceagent for the inks, and/or a treatment with a primer layer for obtaininga uniform background color for the print.

According to a third possibility, the aforementioned decorative toplayer comprises a wood veneer with a thickness of less than 2.5millimeters, for example, of 1 millimeter or less, or a wooden layerwith a thickness of 2 to 5 millimeters, for example, 2.5 to 3.5millimeters.

According to a fourth possibility, the aforementioned decorative toplayer comprises a linoleum layer, a cork layer, whether or not printed,a stone veneer layer, a ceramics layer or the like.

In the cases where the actual decoration is thin, such as with printeddecors or wood veneer or other wood layers, the decorative top layerpreferably comprises a transparent or translucent wear layer providedabove the, possibly printed, decor. Such wear layer preferably comprisesa transparent synthetic material, such as melamine, PVC, PU, lacquer,for example, lacquer on the basis of acrylate, and the like.

Preferably, the panel, at the side directed away from the decorative toplayer, comprises a sublayer of a material which is softer than theaforementioned magnesium oxide-based board material. So, for example,the sublayer may be formed of cork or of a foamed synthetic material.

With the same purpose, however, according to a second independentaspect, the present invention also relates to a panel, more particularlyfloor, wall or ceiling panel, wherein this panel comprises a core and aprovided thereon decorative top layer, characterized in that theaforementioned core comprises a mineral-based board material, whereinthe aforementioned panel, on at least two opposite edges, is providedwith coupling means which allow that two of such panels can beinterlocked at the respective edges, and wherein the mineral-based boardmaterial comprises at least a reinforcement layer, for example, a glassfiber layer. It is clear that the panel of the second independent aspectcan also show the characteristics of the first aspect of the inventionand/or the preferred embodiments of the first aspect of the inventionwithout therein necessarily applying a magnesium oxide-based boardmaterial. Instead of a magnesium oxide-based board material, also agypsum-based or chalk oxide-based board material, or a cement-basedboard material can be applied, such as a board material based onPortland cement, for example, of the type known from the aforementionedWO 2016/156,506.

The panels of the second aspect may show, for example, one or acombination of two or more of the following characteristics:

-   -   the characteristic that the aforementioned reinforcement layer        is situated off center from the thickness of the mineral        based-board material;    -   the characteristic that the aforementioned reinforcement layer,        on the side thereof directed away from said center, is flanked        by a layer of mineral-based material;    -   the characteristic that the aforementioned mineral-based board        material comprises fillers, and that the aforementioned layer of        mineral-based material is free from fillers or comprises less        fillers than a central portion of said mineral-based board        material, and/or comprises fillers with an average particle size        which is smaller than the fillers in a central portion of said        mineral-based board material;    -   the characteristic that the panel comprises at least two such        reinforcement layers, which preferably are situated on opposite        sides of the center of said mineral-based board material; the        characteristic that the aforementioned coupling means are        realized at least partially, and preferably entirely, in one        piece with the aforementioned mineral-based board material.

Preferably, the coupling means of the panels of the second aspect showone or a combination of two or more of the following characteristics,which each separately or in any combination offer interestingadvantages:

-   -   the characteristic that the coupling means offer a locking in        horizontal direction H1 as well as in vertical direction V1;    -   the characteristic that at least one pair of horizontally active        locking surfaces of the coupling means is realized in the        mineral-based board material;    -   the characteristic that at least one pair of horizontally active        locking surfaces of the coupling means is realized at least        partially and preferably entirely in the mineral-based board        material;    -   the characteristic that one or more pairs of the vertically        active locking surfaces are formed at least partially and        preferably entirely from the mineral-based board material;    -   the characteristic that the mechanical coupling means consist of        milled profiles, which for at last 70 percent of their        circumference are provided in the mineral-based board material        of the invention;    -   the characteristic that the panels are rectangular and that a        first pair of opposite edges as well as a second pair of        opposite edges is provided with coupling means;    -   the characteristic that the mechanical coupling means allow a        coupling by means of a turning movement W along the respective        edges and/or a horizontal shifting movement S of the edges        towards each other and/or a downward-directed movement of a male        coupling part, for example, with a tongue, up into a female        coupling part, for example, with a groove; the characteristic        that the lower lip extends in horizontal direction to beyond the        upper lip; the characteristic that in a coupled condition of two        of such floor panels a tension force is obtained between the        respective floor panels; herein, the lower lip of the groove        preferably is in a bent condition;    -   the characteristic that the lower lip of the groove, in a        coupled condition, is bent; the characteristic that the        aforementioned reinforcement layer extends uninterruptedly in        the lower lip; this embodiment is particularly interesting when        a certain bendability of the lower lip is required during        coupling and/or thereafter;    -   the characteristic that the aforementioned reinforcement layer        extends uninterruptedly in the tongue; this embodiment is        particularly interesting with coupling means which have to be        coupled by means of a turning movement, as the weight of the        panels effects, amongst others, on the tongue; the glass fiber        layer restricts the risk of damage to the tongue;    -   the characteristic that the aforementioned reinforcement layer        extends uninterruptedly in the upper lip; this embodiment is        particularly interesting with coupling means which have to be        coupled by means of a turning movement, as the weight of the        panels effects, amongst others, on the upper lip; the glass        fiber layer restricts the risk of splitting off or permanent        deformation of the upper lip.

As aforementioned, the coupling means, on at least one pair of oppositeedges, for example, on the long edges in the case of a rectangular andoblong panel, substantially are realized as a tongue and a groove,bordered by a lower lip and an upper lip, wherein the lower lip shows astanding portion which can cooperate with a locking groove realized onthe lower side of the tongue. Preferably, the coupling means of thepanels of the first and/or the second aspect further show one or acombination of two or more of the following characteristics, which eachseparately or in any combination offer an edge profile which is ideallysuited for being applied in a floor panel with a core of mineral-basedboard material, such as a magnesium oxide-based board material. Thisrelates to the following characteristics:

-   -   the possible vertically active locking surfaces between the        lower side of the tongue and the upper side of the lower lip are        situated substantially, and in this case even entirely, on the        protruding part of the lower lip, namely on that part of the        lower lip which extends beyond the distal end of the upper lip.        Preferably, in the coupled condition there is a space between        the lower side of the tongue and the upper side of the lower        lip, wherein this space preferably extends horizontally        underneath the tongue at least from on the tip of the tongue to        beyond the distal end of the upper lip. In this manner, the risk        of breaking of the tongue when turning the tongue into the        groove is minimized, whereas still a sufficient vertical locking        is obtained; and/or    -   the projection in the horizontal plane of the possible        vertically active contact surfaces between the lower side of the        tongue and the upper side of the lower lip shows a length which        is at least 15%, and still better at least 20% or 25%, of the        length of the protruding part of the lower lip; and/or    -   the length of the protruding part of the lower lip is at least        80% of the thickness of the mineral-based board material and        preferably is smaller than 130% of the thickness of the        mineral-based board material; and/or    -   the smallest width of the standing portion of the lower lip at        the location of the horizontally active locking surfaces is at        least 15% of the thickness of the mineral-based board material        and still better at least 20% of the thickness of the        mineral-based board material; and/or the lower lip of the groove        shows a point or area where the remaining thickness of the lower        lip is smallest, wherein the floor panel comprises a        reinforcement layer which extends in the respective lower lip,        and wherein said reinforcement layer, at the location of said        point or area, is situated off center from the remaining        thickness, preferably, such as here, closer to the upper side of        the lower lip than to the lower side. In this manner, a very        significant effect on the possible bending of the lower lip is        obtained; and/or    -   the upper lip shows a point or area, at the location of the        vertically active locking surfaces, where the remaining        thickness of the upper lip is smallest, wherein the floor panel        comprises a reinforcement layer which extends in the respective        upper lip, and wherein said reinforcement layer, at the location        of said point or area, is situated off center from the remaining        thickness, preferably, such as here, closer to the lower side of        the upper lip than to the upper side. In this manner, a very        significant effect on the possible bending of the upper lip is        obtained

The present invention is particularly interesting when it is applied forfloor panels, as there the advantages, in particular the reducedsensitivity to moisture, of a mineral-based board material are mostpronounced.

Of course, the invention is also of importance when applied in wallpanels or ceiling panels, in particular due to the fire-retarding orfire-resistant features thereof. In particular, the more restrictedweight of magnesium oxide board material is of importance for theinstallation, the packaging and/or the marketing in each application.

The reinforcement by means of one or more reinforcement layers is ofparticular importance in the application of wall panels, in particularwith room-high wall panels, and with panels, for example, wall or floorpanels, with a height, length, respectively, of 2 meters or more. Insuch cases, during installation due to small tolerance differences largepressures on the coupling means will occur, which can lead toirreparable or unworkable damage.

BRIEF DESCRIPTION OF THE DRAWINGS

With the intention of better showing the characteristics of theinvention, herein below, as an example without any limitative character,some preferred embodiments are described, with reference to theaccompanying drawings, wherein:

FIG. 1 represents a floor panel with the characteristics of theinvention;

FIG. 2 , at a larger scale, represents a cross-section according to theline II-II represented in FIG. 1 ;

FIG. 3 represents the coupled condition of the coupling meansillustrated in FIG. 2 ;

FIGS. 4 to 6 , at a larger scale, represent a cross-section according tothe line IV-IV represented in FIG. 1 , however, for variants;

FIGS. 7 and 8 , in a view similar to that of FIG. 3 , representvariants.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 represents a rectangular floor panel 1.

FIG. 2 clearly shows that the floor panel 1 comprises a core 2 and aprovided thereon decorative top layer 3.

The core 2 comprises a mineral-based board material, in this case amagnesium oxide-based board material 4, and, according to the invention,is provided on at least two opposite edges 5-6-7-8, and in this case onthe pair of long opposite edges 5-6 as well as on the pair of shortopposite edges 7-8, with mechanical coupling means 9.

FIG. 2 clearly shows that the coupling means 9 on the long oppositeedges 5-6 substantially are realized as a tongue 10 and a groove 11 withan upper lip 12 and lower lip 13. In this case, the aforementioned lowerlip 13 extends in horizontal direction to beyond the distal end 14 ofthe upper lip 12. The represented coupling means 9 allow at least acoupling by means of a turning movement W along the respective edges5-6. FIG. 3 shows that in the coupled condition a locking is obtained inhorizontal direction H1 perpendicular to the coupled edges 5-6 and inthe plane of the panels 1, as well as in vertical direction V1perpendicular to the plane of the coupled panels 1. The coupling means 9consist of milled profiles, which for at least 70 percent of theircircumference are provided in the mineral-based board material 4. Inthis case, the coupling means 9 are provided practically entirely in themineral-based board material 4 of the core 2, with the exception of thepart 15 thereof formed on the decorative top layer 3.

FIG. 3 represents that at least one pair of horizontally active lockingsurfaces 16-17 of the coupling means 9 is realized in the mineral-basedboard material 4. Herein, this relates to a first pair of lockingsurfaces 16-17 formed on a standing locking portion 18 of the lower lip13 and a cooperating therewith locking groove 19 on the lower side ofthe tongue 10. A second pair of horizontally active locking surfaces20-21 is formed in the example on the decorative top layer 3, or theaforementioned circumference portion 15. Several pairs of the verticallyactive locking surfaces 22-23-24-25 are formed of the mineral-basedboard material 4. Herein, this relates at least to a first pair ofvertically active locking surfaces 22-23 on the upper side of the tongue10 and the lower side of the upper lip 12 of the groove 11, and at leasta second pair of vertically active locking surfaces 25-26 on the lowerside of the tongue 10 and the upper side of lower lip 13 of the groove11. In the example of FIG. 3 , the second pair of vertically activelocking surfaces 25-26 is formed such that they extend at leasthorizontally at a position vertically underneath the aforementionedupper lip 12. In this case, also a third pair of vertically activelocking surfaces 27-28 is formed in the proximity of the aforementionedfirst horizontally active locking surfaces 16-17.

FIGS. 2 and 3 clearly show that at least one, and in this case even aplurality of reinforcement layers 29-30 are applied in the mineral-basedboard material 4. A first reinforcement layer 30 extends uninterruptedlyin the aforementioned lower lip 13; a second reinforcement layer 29extends uninterruptedly in the aforementioned upper lip 12. The firstand second reinforcement layers 29-30 thus are situated off center fromthe thickness T1 of the magnesium oxide-based board material 4. On thesides of the reinforcement layers 29-30 which are directed away from thecenter of the board material 4, they are each time flanked by a layer 31of magnesium oxide-based material. In the example, these layers 31 showanother composition than the central layer 32 of the magnesiumoxide-based board material 4, for example, in that they do contain no orless fillers than the central layer 32 of the mineral-based boardmaterial 4.

It is clear that the core 2, or at least the central layer 32 thereof,preferably is positioned such that it is at least centrally present inthe core 2, namely, on the central line C. In this case, the thicknessT2 of the central layer 32, i.e., the layer between the tworeinforcement layers 29-30, amounts to more than 40 percent of thethickness T1 of the core.

The aforementioned decorative top layer 3 comprises a printed motif 33and represents a single wooden plank. The printed motif 33 is providedon a thermoplastic foil 34, namely, a PVC foil. The floor panel 1further also comprises a translucent or transparent wear layer 35, whichis provided above the aforementioned decoration or printed motif 33.

It is noted that, according to a not represented embodiment, a floorpanel 1 according to the invention may show an additional layer on thelower side of the core 2. Herein, this preferably relates to a foamlayer, for example, of cross-linked or crosslinked polyethylene (XPE),which is fixed to the lower side of the core 2 by means of glue, inparticular is fixed to the layer 31 which flanks the reinforcement layer30. In this case, this relates to a soft foam.

Further, it is noted that in the coupled condition of FIG. 3 a tensionforce can be obtained between the respective floor panels 1, moreparticularly at the location of the second pair of horizontally activelocking surfaces 20-21, namely between the respective decorative toplayers 3 on the upper edges of the coupled floor panels 1. In dashedline 36 in FIG. 3 is represented that such tension force can beobtained, for example, in that the lower lip 13 in the coupled conditionis spring-deflected and in the coupled condition pushes against thetongue 10. Such pretension is known as such, for example, from WO97/47834.

At the opposite short edges 7-8 of the floor panel 1 in the example ofFIGS. 1 to 3 the same coupling means 9 are applied as at the longopposite edges 5-6.

FIG. 4 represents a variant wherein at the short edges 7-8 couplingmeans 9 are provided with a male part 37 and a female part 38, whichallow coupling two of such floor panels 1 at the respective edges 7-8 bymeans of a downward movement M of the male part 37 in the female part38, wherein in the coupled condition a locking in a horizontal directionH1 as well as in a vertical direction V1 is effected. The combination ofa turnable profile on the long edges 5-6, for example, according toFIGS. 2 and 3 , and a downwardly coupleable profile at the short edges7-8, for example, according to any of the FIGS. 4 to 6 , leads to thecreation of a floor panel 1 which can be coupled by means of a so-calledfold-down movement. Herein, the long edges 5-6 are provided in eachother by means of a turning movement W, wherein by this turning movementW at the short edges 7-8 a downward movement M is created, whichprovides the male part 37 present there in the female part 38.

The example of such downwardly coupleable profile represented here ismade in one piece with the mineral-based board material 4 of the floorpanel 1 and comprises, for effecting the locking, a cooperating snaphook 39 and undercut 40, as well as a hook-shaped part 41 on the lowerlip 13, which in this case also shows an undercut 42. The undercut 42 onthe hook-shaped part 41 is made such that it forms an angle A1 with thevertical of 1° to 10° and preferably approximately 5°. The lockinggroove 19, which cooperates with the aforementioned hook-shaped part 41,is positioned entirely underneath the reinforcement layer 29 at theupper surface.

The aforementioned cooperating snap hook 39 and undercut 40 in this casecomprise vertically active contact surfaces 22-23, cooperating in thecoupled condition, which are realized in the mineral-based boardmaterial 4 of the core 2. The horizontally as well as vertically activecontact surfaces 16-17 of the hook-shaped part 41 are also realizedentirely in the mineral-based board material 4 of the core 2.

The upper surface of the lower lip 13 consists entirely of themineral-based board material 4 of the core 2. In coupled condition, theedge profiles also show vertically active contact surfaces 25-26 formedon this upper surface. Between these vertically active contact surfaces25-26 and horizontally active contact surfaces 16-17, a space 43 ispresent. The uppermost reinforcement layer 29 extends in one piece overthe aforementioned locking groove 19 at the lower side of the malecoupling part 37.

At the lower side of the lower lip 13, a recess 44 is realized, whichextends at least partially underneath the aforementioned space 43. Itprovides for a smoother coupling, even with the represented overlap 45in the contours of the male coupling part 37 and the female couplingpart 18 at the location of the horizontally active locking surfaces16-17. The lowermost reinforcement layer 30 is removed at the locationof the aforementioned recess 44. This does not necessarily have to beso. According to a not represented embodiment, the lowermostreinforcement layer 30 can extend in one piece above said recess 44.

FIG. 5 represents a variant of profiles which can be coupled into eachother by a downward movement M, wherein the snap hook 39 is situated atthe distal end 46 of the lower lip 13 of the female part 38, whereas theundercut 40 is provided in the male part 38. Here, too, the uppersurface of the lower lip 13 is formed entirely from the mineral-basedboard material 4 of the core 2, and in coupled condition the edgeprofiles show vertically active contact surfaces 25-26 formed on thisupper surface. Between these vertically active contact surfaces andhorizontally active contact surfaces 16-17, a space 43 is present. Thelowermost reinforcement layer 30 extends in one piece in the lower lip13, and the uppermost reinforcement layer 29 extends in one piece overthe aforementioned locking groove 19 at the lower side of the malecoupling part 37.

In the example of FIG. 5 , too, the hook-shaped part 41 is realized withan undercut 42, wherein this undercut 42 is realized such that it formsan angle A1 with the vertical of 1° to 10°, and preferably approximately5°. It is evident that, in FIG. 4 as well as in FIG. 5 , such undercut42 at the location of the horizontally active contact surfaces 16-17 onthe hook-shaped part 41 is not necessary and that as well contactsurfaces can be used which are vertical or which are less steeplyinclined than the vertical, for example, with an inclination wherein therespective contact surfaces enclose an angle with the horizontal of 45°to 90°.

FIG. 6 represents a variant of downwardly coupleable profiles, whereinthe snap hook 39 is formed by a separate insert 46, which in this caseis provided in the male part 37. Such separate insert 46 preferably isalso formed of thermoplastic material, for example, at least from PVC orABS (Acrylonitrile-butadiene-styrene), and in coupled conditionpreferably shows, such as here, a vertically active contact surface 22with the mineral-based board material 4 of the female part 38. In thismanner, a precise vertical positioning of the male part 37 in the femalepart 38 can be obtained. The aforementioned separate insert 46 issituated, in this example, in a seat 47 with walls, which are entirelyformed from the mineral-based board material 4 of the core 2.

It is clear that the hook-shaped part 41, the cooperating therewithlocking groove 19 on the lower side of the male part 37, respectively,extends in the examples of the FIGS. 4 to 6 each time up into the upperhalf of the core 2, thus, to above the level C.

FIG. 7 represents another variant, wherein the coupling means 9, forexample, the coupling means 9 of the long opposite edges 5-6, show somepreferred characteristics, which each separately or in any combinationoffer an edge profile which is ideally suited for being applied in afloor panel 1 with a core 2 of mineral-based board material 4, such as amagnesium oxide-based board material. This relates to the followingcharacteristics:

the vertically active locking surfaces 25-26 between the lower side ofthe tongue 10 and the upper side of the lower lip 13 are situatedsubstantially, and in this case even entirely, on the protruding part 48of the lower lip 13, namely on that part of the lower lip 13 whichextends to beyond the distal end of the upper lip 12. Preferably, in thecoupled condition a space 49 is situated between the lower side of thetongue 10 and the upper side of the lower lip 13, wherein this space 49,such as here, extends horizontally underneath the tongue 10 at leastfrom on the tip 50 of the tongue 10 up to beyond the distal end of theupper lip 12. In this manner, the risk of breaking of the tongue 10 whenturning the tongue 10 into the groove 11 is minimized, whereas still asufficient vertical locking is obtained; and/or the projection in thehorizontal plane of the vertically active contact surfaces 25-26 betweenthe lower side of the tongue 10 and the upper side of the lower lip 13shows a length L1 which is at least 15%, and still better at least 20%or 25%, of the length L2 of the protruding part 48 of the lower lip 13;and/or

-   -   the length L2 of the protruding part 48 of the lower lip 13 is        at least 80% of the thickness T1 of the mineral-based board        material 4 and preferably is smaller than 130% of the thickness        T1 of the mineral-based board material 4; and/or    -   the smallest width B1 of the standing portion 18 of the lower        lip 13 at the location of the horizontally active locking        surfaces 16-17 is at least 15% of the thickness T1 of the        mineral-based board material 4 and still better at least 20% of        the thickness T1 of the mineral-based board material 4.

FIG. 8 represents another variant, wherein the coupling means 9, forexample, the coupling means of the long opposite edges 5-6, show somepreferred characteristics, which each separately or in any combinationresult in an edge profile which is ideally suited for being applied in afloor panel 1 with a core 2 of mineral-based board material 4, such as amagnesium oxide-based board material. This concerns, amongst others, thecharacteristics already mentioned in connection with FIG. 7 , and thefollowing characteristics, which, however, do not necessarily have to beapplied in combination with those from FIG. 7 :

-   -   the lower lip 13 shows a point 51 or area where the remaining        thickness D1 of the lower lip 13 is smallest, wherein the floor        panel 1 comprises a reinforcement layer 30 which extends in the        respective lower lip 13, and wherein said reinforcement layer        30, at the location of said point 51 or area, is situated off        center from the remaining thickness D1, preferably, such as        here, closer to the upper side of the lower lip 13 than to the        lower side. In this manner, a very significant effect on the        possible bending of the lower lip 13 is obtained; and/or    -   the upper lip 12 shows a point or area 52, at the location of        the vertically active locking surfaces 22-23, where the        remaining thickness D2 of the upper lip 12 is smallest, wherein        the floor panel 1 comprises a reinforcement layer 29 which        extends in the respective upper lip 12, and wherein said        reinforcement layer 29, at the location of said point or area        52, is situated off center from the remaining thickness D2,        preferably, such as here, closer to the lower side of the upper        lip 12 than to the upper side. In this manner, a very        significant effect on the possible bending of the upper lip 12        is obtained.

The present invention is in no way limited to the herein above-describedembodiments, on the contrary can such panels be realized without leavingthe scope of the present invention.

1. A panel comprising a core and a decorative top layer providedthereon; wherein the core comprises a first mineral-based board materiallayer, wherein the panel, on at least two opposite edges, is providedwith coupling means arranged for two of such panels to be interlocked atthe respective edges; wherein the coupling means is arranged for lockingin a horizontal direction and a vertical direction, the coupling meansare formed as a tongue and groove connection such that the groove isbordered by an upper lip and a lower lip, the lower lip extending in thehorizontal direction beyond the upper lip; wherein the core comprises alower mineral-based board material layer, wherein the lowermineral-based board material layer is provided at a side of the firstmineral-based board material layer opposite from a side of thedecorative top layer; wherein the composition of the lower mineral-basedboard material layer differs from the composition of the firstmineral-based board material layer; wherein the core comprises an uppermineral-based board material layer, wherein the upper mineral-basedboard material layer is provided between the first mineral-based boardmaterial layer and the decorative top layer; wherein the composition ofthe upper mineral-based board material layer differs from thecomposition of the first mineral-based board material layer.
 2. Thepanel of claim 1, wherein the lower mineral-based board material layercomprises less fillers than the first mineral-based board materiallayer.
 3. The panel of claim 1, wherein the lower mineral-based boardmaterial layer comprises fillers with an average particle size which issmaller than the fillers in the first mineral-based board materiallayer.
 4. The panel of claim 1, wherein the upper mineral-based boardmaterial layer comprises less fillers than the first mineral-based boardmaterial layer.
 5. The panel of claim 1, wherein the upper mineral-basedboard material layer comprises fillers with an average particle sizewhich is smaller than the fillers in the first mineral-based boardmaterial layer.
 6. The panel of claim 1, wherein the decorative toplayer contacts the upper mineral-based board material layer.
 7. Thepanel of claim 1, wherein first mineral-based board material layer is amagnesium oxide-based material layer.
 8. The panel of claim 1, whereinthe lower mineral-based board material layer is a magnesium oxide-basedmaterial layer.
 9. The panel of claim 1, wherein the upper mineral-basedboard material layer is a magnesium oxide-based material layer.
 10. Thepanel of claim 1, wherein the groove is provided in the firstmineral-based board material layer.
 11. The panel of claim 1, whereinthe upper lip is at least partially provided in the upper mineral-basedboard material layer.
 12. The panel of claim 1, wherein the lower lip isat least partially provided in the lower mineral-based board materiallayer.
 13. The panel of claim 1, wherein the decorative top layercomprises at least a printed decor.
 14. The panel of claim 13, whereinthe decorative top layer comprises a carrier sheet printed with a decor.15. The panel of claim 14, wherein the carrier sheet comprises a papersheet or a plastic foil.
 16. The panel of claim 13, wherein thedecorative top layer comprises a decor formed directly on the core orprinted on the core.
 17. The panel of claim 13, wherein a transparent ortranslucent wear layer is provided above the printed decor.
 18. Thepanel of claim 1, wherein each of the first mineral-based board materiallayer, the upper mineral-based board material layer and the lowermineral-based board material layer comprise cellulose fibers or woodparticles, or both.
 19. The panel of claim 1, wherein the firstmineral-based board material layer is thicker than the uppermineral-based board material layer and then the lower mineral-basedboard material layer.